Emerald
Emerald is a variety of crystallizing in the hexagonal crystal system silicate mineral beryl and having a hardness of 7.5 to 8 is described by its chemical composition Be3Al2Si6O18. The color is green by the addition of chromium and vanadium ions, the line color is white.
Etymology and history
The word " Emerald " was borrowed through the Latin from the Greek Smaragdus σμάραγδος, smaragdos ( green stone ) and is Sanskrit marakatam (green ) is used; probably, however, the word is of Semitic origin, cf akkad. barraqtu " shining stone ", the root BRQ " shine " and Hebrew ברקת ( Bareqet ), " Emerald " to ברק ( baraq ), " flashing ".
The beginnings of the Emerald degradation lie in ancient Egypt. As early as the 13th century BC, the precious stones were collected there; the mines of Sikait and Sabara supplied Europe more than a thousand years with the precious minerals. Also in the East in Persian, Ottoman and the Mogul rulers of India, the precious stones were very popular. When finally conquered the Spaniards in the 16th century South America, they also met there on a brisk trade with the stones, to the extended far to Chile and Mexico from Colombia from. The 1573 of them captured Muzo mine replaced henceforth the Egyptian sources.
1935 succeeded the I.G. Produce colors in Bitterfeld first, synthetic emeralds in to sand quality. They were for promotional purposes under the name Igmerald, a portmanteau of IG and the word for emerald Emerald sold.
Varieties
- Trapiche Emerald - a rare, caused by inclusions and specific growth processes variety in the form of a chariot wheel with six spokes (no twin ), mainly coming from Colombia
- Emerald Cat's Eye - with cats eye effect
Education and Locations
Emeralds are found in pegmatite veins, especially in granites, but also in metamorphic rocks such as gneiss and as a mineral soap in river sediments. The crystals are rarely larger than a few centimeters and usually through cracks, inclusions (often biotite and other micas or liquids) affected and admixtures of other minerals in their quality. Their occurrence is linked to tectonic fault zones. It is possible to prepare synthetic emeralds.
Important reserves are found in Colombia, Brazil and the Ural Mountains. Smaller deposits are found in southern Africa. The only relevant European sites are located in Habachtal in Austria ( emerald mine Habachtal ) and the Byrud Gård in Akershus, Norway. Previously there emeralds were mined, and today one can find as an individual with his own happiness emerald. There are also Egyptian origin for the ancient times.
Use as a gemstone
Emeralds have been and are appreciated by many cultures of the world as particularly valuable jewelry or gems. Especially the emeralds from Brazil can achieve part higher prices than an equally large diamond by their vibrant green.
Large and famous Emeralds
Economic Importance
The emerald deposits is a not to be underestimated economic factor. All producing countries export the stones to a large extent. Emeralds in Colombia exported annually with an official trade volume between 150 and 400 million U.S. dollars, with estimates of the same amount must be added to the black market.
Manipulations and imitations
Emerald is in its optical properties (color, gloss), although very sensitive, it changes color only at about 700 to 800 ° C, but often it shows an uneven color distribution and due to many cracks and inclusions a color turbidity and pressure sensitivity. This is counteracted in the jewelry industry by the stone, for example, stabilized by resins uncolored or colored oils and resins is colored.
As one of the most valuable and correspondingly expensive gemstones the emerald - range is often supplemented by synthetics and imitations. Color- similar minerals such as green colored minerals of the tourmaline, Dioptase and the garnet varieties Dematoid and grossular to be used as well as colored glass.